Navigational instrument



Jan. 14, 1936. R. w. BocKlUs NAVIGATIONAL INSTRUMENT Filed April 22, 1935 4 Sheets-.Sheet` 1 gen1 llllillllllllll INVENTOR RWBOCK/US vATT RNEY Jan. 14, 1936. R. w. BocKlUs NAVIGATIONAL INSTRUMENT 4 Sheets-Sheet. 2

Filed April 22 INVENTOR i?. W BOEK/U5 BY 42W/ ATTNEY Jan. 14, 1936. R, W BQCKfUS 2,027,368

NAVIGATIONAL INSTRUMENT Fild April 22, 1935 4 Sheets-Sheet 3 KO 8d3 Z/ Z/ C) O) Q l o) L "ZZ H6- Z F/- 8- /Z L f fo O O O o) X0 o) H Q 56-/0.

` lNvENToR Rw. 50c/w05 Jap. 14, 1936. R. w. BCKIUS 2,027,368

NAVIGATIONAL INSTRUMENT Filed April 22, 1935 4 sheets-sheet 4 PLA NE DATA CARRIER DATA NEAREST LAND INVENTOR RW. BUCK/U5 Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, I

' amendedApril 30, 1928; 370 O. G. 757) This invention relates to a device for determining the course actually followed or thecourse to be steered by an aircraft, taking into account the direction and velocity of any wind acting thereon and to VsolveV other problems connected with navigation, both aerial and surface.-

It is the object of this invention to provide an instrument of the type specified upon which the v data of a problem may be readily setup and the solution quickly and accurately obtained.v It is also among the objects 'fof this invention to provide an instrument thatis cheap to manufacture, light in weight,` and: that may readily be stowed in the 4ploclirets of flying clothes and be `manipulated by one hand. 1

In the drawings: f Fig. l is a plan view of my inventionvwith parts broken away; y

` Fig. 2 is a plan view of the reverse side of the zo instrument with a portion of an auxiliary device preferably associated therewith removed to show y K plate 22, which may be termedthe ground-speed the said. reverse side of the instrument proper;

Fig. 3 is a section substantially on the `median longitudinal line of the instrument; v. 25 Fig. 4 is a plan view of one of the discs yof the instrument calibrated to read directions corrected for compass variations;

Fig. 5 is the compass rose disc;

Fig. 6 is a disc bearing aline that serves as one f Fig. 13 shows ra convenient sheet for recording l,

certain data;

45 Fig. 14 is a compass rose mounted on v,the grid shown in Fig. 15 and associated with the member in Fig. 1l3tu constitute an auxiliary device.

I am jaware that numerous devices for determining and solving the numerous navigational ao problems encountered inflight have heretofore been proposed and used, butall those with which I am acquaintedI are cumbersome vin size and inconvenient to use in the restricted space of the cockpit of an airplane and many of them require N both hands to manipulate them. The present invention provides an instrument that is sufficiently accurate in all respects and yet may be carried in the flying clothes of the aviator.

My device comprises an opaquey base member I6, preferably of the material commonly called 5 xylonite, having in it perforations I1 for the insertion of a light fastening lmeans and holes I8 in the corners thereof to receive hollow rivets.

A circular cut-out portion I9 provides space for mounting the compass rose with both faces of w the rose flush with the corresponding faces of the plate I6. The elongated cut-out portion 2| permits access to. manipulate the slidable member hereinafter described. inasmuch as several of the members of the device have` perforations that I5 register with the perforationsv I1, have holes in the corners, and elongated cut-out portions adapted to register `with 2l, these features will not be described but merely indicated by the same reference characters as in Fig.' 7. 20 Secured to the member `I6 is a transparent plate, havingon it concentric circles 23 to indicate ground speeds. At the center of the circlesv 23 is a hole 24 through which is passed a fasten- 25 ing means for rotatably securing the compass rose 20 thereto in position in the opening I9 of member I6.

A spacer and guide frame 25 is secured against the plate 22 and provided with an index marker 30 26 on one end thereof alongthe median longitudinal line of the frame. A transparent airspeed plate 21 is slidable in the frame 25 which serves as a guide to insure accurate linear movement oi.' `the member 21 and also as a'spacer to 35 give the plate 21 freedom of movement under the transparent, cover plate 28 that is disposed against the frame 25. The member 21 has inscribed on it air-speed circles 29 and a cross or other indicating mark 30 at the center of these 40 circles. A roughened tab 3i is accessible through the openings 2| to be grasped between finger and thumb to shift the plate 21 longitudinally. Elongated slots 32 receive rivets 33' fixed in the holes 33 in plates 22 and v2li to act as 'additional guide 45 means frthe member 21.

Rotatably mounted upon a rivet in the hole 3| in member 28 is a readerdiscrz=35, the position of the hole 34 being such that disc.- 35 is concentric with the circles 23 on the member 22. An- 50 guiar calibrations 36 are inscribed on the margin of disc X extending in opposite directions from a zero line 31 to cooperate with compass rose 20 and give directly readings corrected for compass variation. A heading-disc 38 is disposed over 5;

ldiseIlandhasonitadiametrallhe"and formed in it, along a radius at right angles to line Il, an elongated slot 40 through which passes a rivet 4I xed in hole 4I in disc II. and also 5 the rivet 84' which secures the disc ll to the plate. Disc Il is thus constrained to rotate with the disc 8i but is slidable with respect thereto along the radius defined by slot 4I. Roughened areas l2 are provided on disc Il to insure adequate fricio tional contact of the operators thumb with the disc and thereby facilitate the sliding of disc 3l. Compass rose is held against displacement from the back of base member Il by a yokeshaped piece 43 of Y transparent material that l5 overlies a portion of the edge of the compass rose. For convenience the compass rose may bear on its rear face scales for computing certain quantities relating to flight, as indicated in Fig. 2, but this constitutes no part of the present 20 invention. 'I'he convenience and neld of use of my device are enhanced by associating therewith a plate u having on one face spaces for recording any data desired. Against the other face of the plate Il is secured a plate I5 having on it a grid 46 and rotatably mounted over the grid ay compass rose 41.

While numerous uses for the present invention will suggest themselves to those skilled in this art its operation in the solution of a specific 30 problem will be set forth. 1f the direction and velocity of the wind are known and a given course is to be made good in an aircraft at a known air speed, the course to be steered and the ground speed can be readily determined.

The manipulation for solving the above stated problem is as follows:

Compass rose 2li is rotated to set the direction from which the wind is coming opposite the index line 26 and the plate 21 is slid to bring the marker or indicium I0 into the position on circles 2l corresponding to the wind velocity at the chosen scale; for example, if for this problem the spacing of circles 23 be taken as 10 knots and the wind velocity is 25 knots per hour the mark I0 would be moved to the position 30' on Pig. 1, the innermost circle 2l being the 20 knot circle to `prevent overcrowding at the center. Disc 3l is then rotated about the rivet 34' and slid on disc l5 until the diametral line Il passes through the point 30' and also through the point on compass rose 20 representing the course to be made good. If the compass variation is zero the course to be steered is then read on compass rose Il opposite line 31 or, as is usually the case, correc- I 66 tion is made for the compass variation by reading'on disc 20 the course to be steered opposite the calibration of the variation. The ground speed is represented by the position, with respect to circles 2l, of 00 the intersection of line 39 and the circle 20 which represents the air speed of the craft. If the circles 2l and 20 are considered to represent 10 knot intervals the set-up shown in Pig. l would be interpreted as follows, assuming a com- ,65 pass variation of l5 west:

The position of point 3l indicates a wind velocity of 45 knots and a wind coming from 0 true. Ihe course tobemade good is shown to be' 250 andiftheh'medbe 100 knotsthentheground 10 speed is indicated at lvl as lbeing ll0- knotsand the compass course to be steeredisshowmopposite the calibration 16 west on scale 30 asbeing 285.

The application of this inventionto the solu- Jl tion of other problems involving-vector ytriangles I0 representing the. magnitudel willbeapparenttothaseskllledinthenavgang art.

The`in`vention described herein may be manufactured and used by or for the Government of the United States for governmental purposes 5 without the payment of royalties thereon.

I claim:

1. A navigational instrument, comprising a base plate, having a circular aperture therein, a compass rose disposed in said aperture, a trans- 10 parent ground-speed plate disposed on said base plate and having on it equally spaced circles concentric with said compass rose, means rotatably securing said rose to said ground-speed plate, a spacer frame disposed on said ground-speed plate, 15 an air speed plate of less length than the aforesaid plates slidable in said frame on said groundspeed plate having a roughened tab extending from one end thereof and having on it air-speed *l circles and a wind velocity indicium at the center m of said air-speed circles; a transparent plate disposed over said spacer and said air-speed plate; said base, said ground-speed plate, said frame and said transparent plate being all secured together l at their margins, and said base. said ground-speed plate and said transparent plate being apertured to give access to said tab to slide said air-speed plate; a reader-disc rotatably secured to said transparent plate hconcentrically with said rose having on its margin compass variation indicia go and a reader-line, and a heading-disc mounted on said reader-disc to rotate therewith and to be radially slidable thereon, said heading-disc having a diametral line movable by sliding said heading-disc and turning said reader-disc to pass gs through said wind velocity indicium and through any selected point on said compass rose.

2. A navigational instrument, comprising a base plate, having a circular aperture therein, a compass rose disposed in said aperture. a transo parent ground-speed plate disposed on said base plate and having on it circles representing ground-speeds concentric with said compass rose and to which said rose is rotatably attached, a spacer frame disposed on said ground-speed plate, u an air-speed plate of less length than the aforesaid members disposed to slide on said groundspeed plate within said frame as a guide, said airspeed plate having thereon concentric air-speed circles anda wind velocity indicium at the center so of said air-speed circles and a tab extending from one end, a transparent plate over said spacer and said air-speed plate; said base, said ground-speed plate. said spacer and said transparent plate being all secured together at their margins and said as base, said ground-speed plate and said transparent plate being all apertured to give access to said tab; a reader-disc rotatably secured to said tramparent plate concentrically with said rose having on its margin compass variation indicia readable l0 in conjunction with said rose, and a heading-disc mounted on said reader-disc to rotate therewith and movable with respect thereto to set a diametral line on said headingdisc to pass through said wind velocity indicium and through any Il chosen point on said compass rose.

3. A navigational imtrument, comprising a transparentamnnd peed member having a plurality of concentricl circles thereon, a compass rose; -rotatably'secured to the under side of said 'lo member concentrically with said circles, an airspeedplate accurately moimted to be slidable on said member parallel to one edge only of said plate and having on it concentric circles and a wind velocity indicium at the center of said con- 1s centric circles thereon and a tab extending from one end thereof, a transparent plate over said airspeed plate, there being apertures provided in said member, said airspeed plate and said transparent plate to give access to said tab, a rst disc rotatably mounted on said transparent plate concentrically with said rose and a second disc mounted on said first disc to be rotatable therewith and to be slidable radially thereof, said second disc having on it a diametral line that maybe brought into coincidence with said wind velocity indicium and with any chosen point onl said rose, and the first disc having on its margin indicia readable in conjunction with said rose corresponding to compass variations of diiIerent magnitudes.

4. A navigational instrument, comprising rotatable means to indicate compass directions, ilxed means bearing concentric ground speed circles associated therewith, meansl bearing concentric air-speed circles and a windvelocity indicium at the center thereof movable parallel to a ilxed line and settable to position said indicium at the center of said ground-speed circles, a first disc rotatably mounted concentrically with said rotatable means, and a second disc mounted on the ilrst disc to rotate therewith and to be settable parallel to one radius of the first disc, said second disc having on it a line that may be made to coincide simultaneously with said indicium and a chosen compass direction on said rotatable means, and said iirst disc having indicia readable in commotion with said rotatable means to indicate a direction that is a function of the setting oi' the rotatable means of the position of the indicium oi.' said chosen compass direction and of the compass variation.

5. A navigational instrument, comprising direction indicating means settable to indicate a parts to be slidable with respect thereto for indicating a wind velocity on said ground-speed circles, a rst disc rotatably mounted concentrically with said ground-speed circles and a second disc slidably mounted on said ilrst disc. there being on said second disc a line movable to cooperate with said indicium and a chosen direction on said direction indicating means to `:form one side of a vector triangle, said rst disc bearing compass variation indicia readable in conjunction with said direction indicating means to show the heading to be steered to make good the course indicated by said chosen direction, the ground-speed being indicated on said groundspeed circles at the intersection of said line and the circle corresponding to the airspeed.

6. A navigational instrument, comprising a direction indicating member settable to indicate a wind direction, a member bearing ground-speed circles operatively associated therewith, a member bearing airspeed circles and at their center a wind Velocity indicium settable to indicate a wind velocity on said ground-speed circles, a member settable, to define a line that includes said indicium and a chosen point on said first mentioned member, the intersection of said line with a chosen air-speed circle indicating a ground speed that is a function of said chosen airspeed, of the wind vector, and of the direction of said line, and means to read on said iirst member a direction that is determined by the directional position of said line, of said wind vector and oi.' the compass variation.

ROBERT W. BOCKIUB. 

